Victoria’s Secret showed off its latest designs at a fashion show Wednesday, and, no surprise, there were some extravagant and pricey items on display. But this pricey?

Model Candice Swanepoel strutted down the runway wearing a $10 million “Royal Fantasy Bra,” the most recent incarnation of the retailer’s annual tradition of highest-end “fantasy bras.” She told ABC earlier that the bra—$2 million belt included—comprises 4,200 gems, with a 52-karat ruby.

The fashion show, to be aired on CBS Dec. 10, was a star-studded event complete with a performance by Taylor Swift and appearances from models Cara DeLevingne and Behati Prinsloo among others.

But investors may want to take note. The iconic brassieres have varied in value over the past two decades, and an analysis by CNBC suggests the bra’s price tag in a given year may well be a good indicator for the stock market.

In fact, prices for the “fantasy bras” tracked the S&P 500 index up or down every year since 1996 except once, in 2003. During the booms, prices soared, including the record $15 million “Red Hot Fantasy Bra” (not terribly safe for work) in 2000. During the busts, prices fell: this year’s $10 million value is the highest since 2005.

To be sure, it’s not the bra market determining these prices. The unidentified person who purchased last year’s $2.5 million bra is the only buyer to date, according to CNBC.